Flexible Fixture Device with Magneto-Rheological Fluids

In manufacturing, fixtures are required to locate parts in a correct position to ensure machining accuracy. Especially for machining on irregular-shaped work-pieces and fine parts, flexible fixtures are in demand to reduce non-machining time. The quick phase change and strong yield strength of MR fluids lead us to investigate the possibility to produce MR-fluid-flexible-fixture. The yield strength and pre-yield elastic modulus are the key issues for a flexible fixture. However, a typical MR fluid currently has yield stress about 100 kPa that is not sufficient for flexible fixtures. To overcome the difficulties, we apply pressure to force single chains into thick columns. This produces a structure-enhanced yield stress. MR fluids in this process produce a yield stress of 800 kPa or above under a moderate magnetic field. The three-dimensional load capacity of MR fluids in this process is strong enough to ensure precision manufacturing. In addition, MR-fluid-flexible-fixtures are environmentally friendly and work at room temperature.